Double threading clip



Nov. 22, 1966 s. H. SATHER 3,286,319

DOUBLE THREADING CLIP Filed March 25, 1965 2 Sheets-Sheet l FIGI.

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DOUBLE THREADING CLIP Filed March 25, 1965 2 Sheets-Sheet 2 INVENTOR; BYSTANLEY H. SATHER ATTVS' United States Patent DOUBLE THREADING CLIPStanley H. Sather, New Westminster, British Columbia,

Canada, assignor to Aktiebolaget Svenska-Flaktfabriken, Stockholm,Sweden Filed Mar. 23, 1965, Ser. No. 442,004 12 Claims. (Cl. 24253) Myinvention relates to a double threading clip, used particularly in pulpmills, for threading wet or dry material int-o processing machines. Suchmaterial is normally a web. Single threading clips are well known in theart; my double threading clip is used in the same manner as a singleclip.

A double threading clip is claimed in the copending application ofAlphons Livio Rosenqvist filed August 28, 1964, under Serial Number392,798, and therefore my disclosure herein is confined to the structureof my invention, to a novel method of continuous winding of a multiplespring element thereof, and to a novel method of winding a discreteunit, a plurality of which form an alternative spring embodiment.

Single threading clips are adapted to grasp one side of the web. Thisplaces an unequal pull upon said web, a disadvantage which is generallyrecognized in the industry.

An obvious solution appears to be a double clip, which could overcomethis disadvantage above by grasping both sides of the web at once.Heretofore, attempts to provide double clips have not been entirelysuccessful and, accordingly, at the present time, single clips are ingeneral use both in European and North American mills, and elsewhere.

One difficulty has been to provide adouble clip having a base portionwith the required strength and (flexibility.

My clip includes a body having a base, integral with the body foldableflap elements on each side of the base, the flap portions about half thewidth of the base portion and strongly urged against said base by springmeans. In this way grip is effected upon both sides of the web.

It will be understood that, pulling from a central strap of such a clip,stresses are introduced tending to cause the base to collap-sewhichdifiiculty is encountered in previous attempts to provide a practicaldouble clip. 1

In one way I provide the necessary strength and rigidity maintaining therequired flexibility, by transverse spring elements integral with thespring means used to urge the flaps against the base, the multiplespring formed from a continuous length of spring wire.

An alternative spring means having such strength, rigidity, andflexibility is provided by a multiple spring assembled from a pluralityof discrete units, each unit having transverse members. In such adiscrete unit multiple spring assembly, contiguous transverse elementsof adjoining units are secured together thus giving greater transversestrength which, in some cases, may be an advantage.

Another advantage of the discrete unit construction is that a stock ofsuch units may be prefabricated, thus spring elements for threadingclips of different lengths may be assembled at will. Further, thediscrete units themselves are well adapted to be produced bycomparatively simple automatic winding machinery.

An important object of my invention is to provide a such spring eithercontinuously formed, or assembled from discrete units, the multiplespring having transverse elements cooperating with helical springelements and generally triangular loop elements, by means of whichcooperation the necessary gripping closure is effected, said transverseelements suitably reinforcing the base.

A further important object is to provide a quick, cheap and simplemethod-of winding a multiple spring of and from a continuous length ofspring wire.

3,286,319 Patented Nov. 22, 1966 Still further important objects are toprovide a such spring assembled from a plurality of discrete elements,and to provide a quick and simple method of winding a said discreteelement.

Other objects and advantagesof my invention, the construction thereof,and the spring winding methods, will be apparent to those skilled in theart from the following detail description and drawings.

FIG. 1 is a plan view of a clip according to the present invention,

FIG. 2 shows the clip as it would appear in plan with the foldable flapsfully open,

FIG. 3 is a section on line 33 of FIG. 1, and is diagrammatic,

FIG. 4 shows one embodiment of the multiple spring, and is illustrativeof the method of continuous winding,

FIG. 4A is a cable clamp, in perspective at enlarged scale,

FIG. 5 is a discrete unit of an alternative multiple spring embodiment,and

FIG. 6 is a multiple spring assembled from a number of discrete units asFIG. 5.

In the drawings, the springs are shown diagrammatically.

Referring to FIGURES 1, 2, and 3, the threading clip indicated generallyby the numeral 10 has a double envelope body portion 11, and integraltherewith the generally triangular part 12 extending outwardly from 11.Securely stitched to the outer apex 13 of member 12 is the strap or beltmember 14, suitably strong burlap, which strap also is secured to acable, as later explained.

As best seen in FIGURE 3, the double envelope 11 of strong canvas orlike material, has a base 15, the triangular part aforesaid, and thefoldable flaps 16 and'17. As seen in FIGURE 2, the flap 16 folds alongthe broken line 16A, and the flap 17 along the broken line 17A, toassume the positions shown in FIGURES 1 and 3. Side edges of the baseportion are defined by said broken lines.

FIGURE 3 is diagrammatic, dimensions at right angles to the plane ofFIGURE 1 being exaggerated. The body '11 is double having an inner layer18 and an outer layer 19. Between these two layers is secured a multiplespring indicated by the numeral 20, serving to urge the foldable flaps16, 17 to the closed position, FIG- URE 3. The multiple spring 20 may bethe continuous embodiment FIGURE 4-, or the discrete unit assembly shownin FIGURE 6.

FIGURE 2 shows the clip with the flaps 16, 17 fully open better toillustrate the construction. In use, the flaps are opened only to aboutto permit insertion of the web to be grasped, say to the extent shown inFIGURE 3 by the broken lines 21. It will be understood that, as theflaps 16, 17 are strongly urged to the closed position, FIGURE 1, by themultiple spring member, force is required to hold them in such brokenline position.

The multiple spring is an important element of my invention. Theconstruction of one embodiment, and a method of winding it from acontinuous length of spring wire stock, are described below withparticular reference to FIGURE 4.

In FIGURE 4 only, the numeral 22 indicates generally a such multiplespring, having two aligned rows 23 of helical elements designated 24.1,24.2 etc, transverse elements designate-d 25.1, 25.2 etc. extendingbetween the two aligned rows as shown, and generally triangular loopelements designated 26.1, 26.2 etc., each triangular element having anapex A adjacent the helical elements aforesaid, and a base B outwardlydisposed substantially parallel to the rows 23.

A preferred method of winding a such multiple spring includes thefollowing steps, the winding is carried out from a continuous length ofsteel spring wire from a spool obviously supported by means, not shown,to permit any required length of wire to be drawn from the spool. In thedescription, the terms clockwise and counter clockwise refer toclockwise and counterclockwise springs as indicated by the directionalarrows in FIGURE 4, and as viewed from the right hand side of thefigure. This is not necessarily the direction of winding on a mandrel toproduce the required spring.

Method] (1) Upon a suitable mandrel wind 21 first clockwise helicalelement 24.1. The diameter of the helix, the number of turns, and thediameter of the spring wire are determined from ordinary designprocedures. Sixteen turns of Number 14 American Wire Gage (AWG) wirewound upon a V inch diameter mandrel is satisfactory.

(2) Remove the first helix from the mandrel and wind the secondclockwise helical unit separated from 24.1 by the length of thetransverse element 251, the second unit to lie on a side of 25.1opposite to that upon which the first said helical unit is formed. Therehave now been produced, the first helical element 241, the transverseelement 25.1, and the second helical element 24.2, the axes of the twohelical elements being substantially parallel and separated by the saidtransverse element, and upon opposite sides thereof.

(3) Using a suitable jig, form a triangular loop element 26.1 adjacentthe second helical element 24.2, having a base B disposed outwards andan apex A disposed inwards adjacent the helix 242. Secure the loop witha clamp 27 at the apex A. The axes of the helical elements, thetransverse element 25.1, and the triangular element 26.1, aresubstantially coplanar as formed.

(4) Next wind a third counter clockwise helical element 24.3 coaxialwith 24.2, and closely adjacent to the apex A of 26.1.

(5) Form a second transverse element 25.2 extending to the end of 25.1adjacent the first helical element 24.1, and secure the first and secondtransverse elements to one another adjacent 24.1, by aflixing a cableclamp 27 as shown.

(6) Wind the counter clockwise helix 24.4, aligned with 24.1.

(7) Form the second loop element 26.2 in the manner indicated in step(3), adjacent the helical element 24.4.

(8) Repeat steps (1) to (5) until the required length of multiple springis attained.

(9) Upon completion of step (8), a helix is required to complete the rowof helices of which 24.1 is the first element; wind a final counterclockwise helical element 24-L-1 to complete this row.

(10) Extend the wire to the second helical row to form the lasttransverse element 25L and secure this by a clamp 27 to the adjacenttransverse element.

(11) Finish off with the final helical element 24-L-2 of the second row,which element is clockwise, and cut the wire off at the end of 24-L-2thus completing the multiple spring.

The clamps referred to herein are common cable clamps obtainablecommercially in -a number of styles and sizes. A clamp such as thatshown at enlarged scale in FIGURE 4A is suitable. This is a metal clampadapted to be secured by crimping.

The foregoing steps will have provided a multiple spring 22, with twoaligned rows of helical elements separated by transverse elements andhaving outwardly extending triangular elements with their bases parallelto the helical axes and of such length as may be required.

It is to be understood that the length of the rows of helical springs isaccording to the length of the foldable flaps 16, 17; that theseparation of the helical rows, and thus the length of the transverseelements, is according to the width of the base of the body of the clip,see FIGURES 1 and 2, and that the size of the 4 triangular loop elementsis according to the width of the foldable flaps 16, 17.

The cable 28 FIGURE 4 extends through the first row of helical springs,thence outwardly around the periphery of the triangular portion 12 ofthe clip base, as shown in FIGURES 1 and 2, through the second helicalrow. Suitable cable diameter is inchthat is, about 0.10 inch. A suitablelength of such cable is inserted through the helices as above, andsecured at each end by the clamp means 27A, FIGURE 4-. As seen inFIGURES 1 and 2, the cable is secured to the strap 14 to which the loadis applied. To prevent the cable being pulled out of the helices as theload is applied in use, the clamps 27A should be brazed or soldered tothe cable. Crimping is however adequate to secure the other clamps.

The 4 inch diameter mandrel gives to the helices wound of No. 14 wire aninside diameter such that the cable may readily be inserted. It will beunderstood that the diameter of the wire and of the mandrel, cablediameter, and the number of turns in each helix, as given are by way ofexample only, and are capable of variation.

According to the requirement, the number of turns of the helices may befrom about 10 to about 20, the wire may be, say No. 12 AWG, or as smallas No. 16 AWG, and the mandrel diameter may be between 0.06 and 0.25inch. It is not essential that all the helices of a row have the samenumber of turns.

In making the completed clips, I prefer to make the multiple springfirst.

As shown in FIGURE 4, the multiple spring 22 is untensioned. Tensioningis effected by rotating the lefthand triangular elements clockwisethrough and the right hand triangular elements counter clockwise to thesame extent.

I prefer to fabricate my threading clip by placing the tensioned spring,held tensioned by suitable jig means, upon the outer canvas layer 19,previously cut to size, then assembling the inner canvas layer 18thereto, the tensioned triangular elements therebetween. Suitablefabricating procedure will readily be apparent to those skilled in theart; therefore I shall not describe that procedure in detail. It ishowever to be understood that the multiple spring must be stronglyfastened, by stitching and/or other means, to the canvas structure and Iprefer to use a latex or similar adhesive supplementary to stitching.The strap 14 is strongly secured to the cable 27 by looping andstitching, or by other suitable means. Plastic dabs 29 are applied, asis common practice, to the outer canvas over the position of the severalclamp means 27 to prevent wear. Friction pads 30 are also provided,according to common practice, better to grip the web.

In certain circumstances it is desirable to provide additional strengthin the transverse members of the multiple spring. I accomplish this inone way by making up the spring from discrete units as illustrated inFIGURE 5 and designated generally by the numeral 31.

A method of winding a such unit to provide the required structure isdescribed as follows, referring to FIG- URE 5. Spring wire diameter andmandrel diameter are as before stated with reference to Method I, andclockwise and counter clockwise have the before-stated meanings.

Method 11 (1) A short distance from the free end of the wire stock, asindicated by the broken line 32', wind a first short clockwise helix 32,of two or three turns, cut off the portion 32'.

(2) Now wind a clockwise helical spring 24A1 as before described withreference to springs 24 of Method I. This helix is Wound at a distancefrom helix 32 equal to the length of a transverse member 25A1.

(3) Next form the triangular loop 26A as described in step (3) of MethodI securing the apex A by a clamp 27.

(4) Now wind a counter clockwise helix 24A2 coaxial with 24A1.

(5 At a distance from 24A2 equal to the length of the transverse element25A2 wind a second short counter clockwise helix 31, of two or threeturns. Cut the wire stock at the end of helix 33.

(6) Fasten the two transverse elements by a clamp 27 placed close to theshort helices 32, 33.

This completes a discrete unit. It is to be understood that the variouselements are, as before, coplanar.

A number of discrete units 31 may readily be assembled to a cable 28 toform a discrete unit multiple spring having the general configuration ofthe FIGURE 4 spring, but differing therefrom in that the transverseelements are duplicated. A such discrete unit assembly is illustrateddiagrammatically in FIGURE 6.

One end of the cable 28 is passed through the helices 24A1 and 24A2 ofthe first unit designated 31-A, and the other end is passed through thefirst and second short helices 32 and 33 thereof. The cable is nowpassed through helices of the second unit 31B, which second unit is soplaced that the triangular elements 26A and 26B of the first and secondunits are disposed outwards as shown. The now adjacent transverseelements of the first and second units are secured together by one ormore clamp means 27.

Additional units are added in the same manner until an assembly of therequired length is obtained. When the ends of the cable passing throughthe helices of the last unit are secured by the clamp means 27A,corresponding to and for the same purposes as clamps 27A, FIGURE 4, theclamps 27A, should be soldered or brazed to the cable as before. In theFIGURE 6 discrete unit multiple, the short helices of a number ofintermediate units may be soldered or brazed to the cable additionallyto secure the cable to the spring.

The discrete unit multiple spring embodiment is assembled as previouslydescribed.

In Methods I and II it is specified that the first helix be clockwise.The first helix may be counterclockwise, but, if this were done, all theremaining springs would be changed also, i.e., clockwise where contra isstated, and vice versa.

When the sequence of direction outlined in the methods is followed (orthe reverse sequence) the triangular and transverse elements will lieflat against the base and flaps. If the relative sequence is notfollowed, the resultant multiple spring will still be operable but thetriangular apices and the points of junction of the transverse elementswill (or may, depending upon what particular sequence is followed) beseparated by a distance equal to the diameter of the helices.Accordingly, I prefer to use the sequences indicated, or the reversethereof.

It is to be taken that the foregoing disclosure and detailed descriptionis not intended in a limiting sense, but is by way of example, and thatmodified and alternative embodiments may readily be made within thescope of the present disclosure.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a double threading clip for leading a web through a processingapparatus, said clip including a body of flexible material including abase portion and flap members foldable thereagainst with spring means insaid body to urge said flaps against said base,

the improvement wherein said spring means comprises a multiple springincluding first and second aligned rows of helical spring elements, therows being disposed along opposite side edges of the base and being inspaced, parallel relationship with one another; said springs comprisingdiscrete units each including (a) transverse elements; (b) two rows ofhelical members joined by said transverse elements; (c) an outwardlyextending element intermediate adjoining helical elements in at leastone of said rows; (d) ends on said transverse members, intermediateadjoining helical elements in the other of said rows and (e) means tofasten the transverse members together near said ends,

and means to fasten a discrete unit to an adjoining discrete unit toform said multiple spring.

2. In a double threading clip a multiple spring for closing said cliponto a web comprising a first row of aligned helical spring elements, asecond row of aligned helical spring elements, transverse elementsextending from between the helical elements of the first row to betweenthe helical elements of the second row, and holding elements extendingoutwards of each row of helical spring elements from between theelements of each row and cooperable with said transverse elements toeffect closing of said clip.

3. A multiple spring means as claimed in claim 2, wherein the saidspring is formed from a continuous length of spring wire.

4. A spring means as claimed in claim 2 wherein said spring is formed ofa plurality of discrete units; each such unit including two rows ofhelical spring elements, transverse elements joining the two rows ofhelical elements, an outwardly extending element within at least one ofsaid rows, the transverse members having ends Within the other of saidrows, and means to fasten the transverse members together near saidends; and means to fasten together adjoining discrete units of themultiple spring with the said one row of one unit in alignment with thesaid other row of the adjoining unit.

5. A spring means as claimed in claim 4 wherein the fastening meanssecures the contiguous transverse members of adjoining units to oneanother.

6. A spring means as claimed in claim 4 including a length of flexiblecable extending axially through the first said row of helical springs;thence in an opposite direction through the second said row; fasteningmeans at each end of the cable to secure the same against withdrawalfrom the said rows; the length of the cable being such as to provide aslack portion between the rows; the slack portion adapted for attachmentto a strap of a double threading clip, the ends of the transversemembers being attached to said cable.

7. A spring means as claimed in claim 6 wherein the attachment comprisesa short helix of two or three turns in said other row for the passage ofthe cable therethrough.

8. A spring means as claimed in claim 2 including a length of flexiblecable extending axially through the first said row of helical springsthence in opposite direction through the second said row; fasteningmeans at each end of the cable to secure the same against Withdrawalfrom the said rows; the length of the cable being such as to provide aslack portion between the rows, the slack portion adapted for attachmentto a strap of said double threading clip.

9. The method of winding a multiple spring for a double threading clip,using a continuous length of spring wire comprising the steps of:

(1) winding a first helical element in one direction;

(2) similarly winding a second helical element in the one directionseparated from the first helical element by the length of a transverseelement, the helical elements being parallel and extending in oppositedirections from the transverse element;

(3) forming a first generally triangular element having an apex at theend of the second helical element, and a base parallel to the helicalelements, said base at the side of the second helical element remotefrom the first helical element, and coplanar with the helices, andsecuring sides of the triangular element to one another near said apex;

(4) winding a helical element in the opposite direction constituting athird helical element, the third said element being coaxial with thesecond said element, thus providing two elements of a first row ofhelical elements, the apex of the first triangular element beingdisposed between said second and third helical elements;

() forming a second transverse element by extending the wire from thethird helical element to the end of the first transverse elementadjacent the first helical element, and securing the transverse elementsto one another adjacent said first helical element;

(6) winding a fourth helical element in the opposite direction coaxialwith the first said helical element, thus providing two elements of asecond aligned row of helical elements;

(7) forming a second triangular element thus providing a secondtriangular element extending outwards of the second said row of helicalelements, and coplanar with the transverse elements;

(8) severing the continuous length of spring wire after the requiredlength is obtained.

10. The method as claimed in claim 9 using steel spring wire having anAmerican Wire Gage number between the limits No. 12 and No. 16, andwinding helices having between and 20 turns, using a mandrel having adiameter between 0.06 and 0.25 inch.

11. The method of winding a discrete unit of a multiple spring for adouble threading clip, comprising the steps of:

(1) at a short distance 'from the free end of a reel of spring wire,winding two or three turns in one direction, said two or three turnshaving an axis;

(2) at a distance from the said turns equal to the length of atransverse member, winding a first helical element in said onedirection, coplanar with and parallel to the aforesaid axis of the twoor three turns, the first helical element disposed substantially atright angles to the transverse element and extending from tion, being asecond such element, coaxial with the first helical element;

(5) extending the spring wire to the turns thus formed to form a secondtransverse member, winding a second two or three turns in the oppositedirection coaxial with the first said turns, cutting the wire stock andsecuring the first and second transverse elements together adjacent saidturns.

12. The method as claimed in claim 11 using steel spring wire having anAmerican Wire Gage number between the limits No. 12 and No. 16, andwinding helices having between 10 and 20 turns, using a mandrel having adiameter between 0.06 and 0.25 inch.

References Cited by the Examiner UNITED STATES PATENTS 390,096 9/1888Regan. 2,824,590 2/1958 Anderson. 3,085,346 4/1963 Allander et a1. 34-10FOREIGN PATENTS 51,614 10/1932 Norway.

WILLIAM FELDMAN, Primary Examiner. DONALD A. GRIFFIN, Examiner.

2. IN A DOUBLE THREADING CLIP A MULTIPLE SPRING FOR CLOSING SAID CLIPONTO A WEB COMPRISING A FIRST ROW OF ALIGNED HELICAL SPRING ELEMENTS, ASECOND ROW OF ALIGNED HELICAL SPRING ELEMENTS, TRANSVERSE LEMENTSEXTENDING FROM BETWEEN THE HELICAL ELEMENTS OF THE FIRST ROW TO BETWEENTHE HELICAL ELEMENTS OF THE SECOND ROW, AND HOLDING ELEMENTS EXTENDINGOUTWARDS OF EACH ROW OF HELICAL SPRING ELEMENTS FROM BETWEEN THEELEMENTS OF EACH ROW AND COOPERABLE WITH SAID TRANSVERSE ELEMENTS TOEFFECT CLOSING OF SAID CLIP.